Closed coke slurry system and method for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit
The invention relates to a closed system and method for gaining sellable petroleum coke pieces out of solidified petroleum coke in a coke drum unit.
Petroleum coke is produced through a thermal cracking process as part of the hydrocarbon processing industry. Oily residue streams are heated up in a furnace coil and routed into a coke drum. The furnace effluent composition bonding breaks into light hydrocarbons and ultimately in solidified petrol coke. The light hydrocarbons will be sent into refinery downstream units for further processing.
The produced petroleum coke fills the coke drum from bottom to top continuously. As soon as one coke drum has been filled up, the oily residue will be switched to another empty coke drum.
In order to remove the solidified petroleum coke from the full coke drums, traditionally the so-called pit/pad-system is applied. The pit/pad-system comprises a large open concrete floor in front of the coke drums. The coke is cut out of the coke drum at high temperatures by means of high pressure cutting water, and the coke chunks together with the cutting water is gushed onto a pit floor. Entrainment water flows sideways through a labyrinth, and drain water is pumped into settling and subsequent clean water tanks for recycling. The coke chunks pile up and rest in the pit/pad, until they are taken out of it and fed to a crusher located nearby by means of manually operated overhead cranes or manually operated front loaders. The broken coke pieces are then conveyed to the loading facilities.
A coker with such pit/pad system comprises huge steam clouds engulfing the coker unit, that can be seen from great distances.
Such pit/pad system has a high impact to the atmosphere, since a large amount of steam polluted with coke fines discharges into the atmosphere. The steam contains hydrocarbons, coke dust and aerosols. This causes health problems to the operational and maintenance personnel, especially if they have been exposed to such pit/pad system over a long time. Further, such pit/pad system requires a substantial amount of manual work, especially for operating the overhead cranes or the front loaders, for coke crushing and sludge handling.